Peel and grate the purple sweet potatoes.

In a large bowl, combine the grated sweet potatoes, potato starch, thinly sliced scallions, finely chopped serrano chiles, lightly beaten eggs, kosher salt, and black pepper.

Stir until all ingredients are well blended.

Heat 1/4 cup of coconut oil in a large nonstick skillet over medium-high heat until shimmering.

Spoon 2-tablespoon portions of the potato mixture into the skillet, flattening each portion into a 1 1/2-inch disk.

Cook until crisp, about 4 minutes.

Turn the latkes and cook until crisp, 3 to 4 more minutes.

Drain the cooked latkes on paper towels.

Keep the latkes warm in a single layer on a baking sheet in a 175°F oven.

Repeat the cooking process twice with the remaining coconut oil and potato mixture.

Place the warm latkes on a serving platter.

Top each latke with 1 teaspoon of sour cream and 1/2 teaspoon of tobiko.

Sprinkle with very thinly sliced chives.